[vurpo]

It's not known that there was a single point in time that was the start of our universe. Our current models can pretty reliably calculate the history of the universe back to a specific point, which would be 10^-32 seconds after this big bang point in time, but those models don't work earlier than that.

You could do some extrapolation on the expansion of the universe and just say that yes, there was a point zero, 10^-32 seconds before the earliest point in time that our models can understand, and that's where everything started from a singularity. But then we are still left with a short period of time at the start, where some physics happened that we don't have a working model for.

So since an extrapolated expansion of the universe from a singularity doesn't work in our currently understood models (at least not in the very earliest part of that timeline), is it not then plausible that something other than that expansion from a singularity could have happened during this early unknown period of time?